$A$ man moves $20 \, km$ downstream in $5 \, hours$ and $10 \, km$ upstream in the same time. The speed of the stream is...........$km/h$.

$A$ boat moves downstream at the rate of $1 \, km$ in $10 \, minutes$ and upstream at the rate of $4 \, km/h$. What is the velocity of the current (in $km/h$)?

$A$ man can row $7 \frac{1}{2} \, km/hr$ in still water. If in a river running at $1.5 \, km/hr$,it takes him $50 \, minutes$ to row to a place and back,how far off is the place? (in $km$)

Speed of a motorboat in still water is $45\, km/h$. If the motorboat travels $80\, km$ along the stream in $1\, h\, 20\, min$,then the time taken by it to cover the same distance against the stream will be:

Speed of a man is $10 \text{ km/h}$ in still water. If the rate of current is $3 \text{ km/h}$,then the effective speed of the man upstream is ....... $\text{km/h}$.

There is a road beside a river. Two friends started from a place $A,$ moved to a temple situated at another place $B$ and then returned to $A$ again. One of them moves on a cycle at a speed of $12\, km/hr,$ while the other sails on a boat at a speed of $10\, km/hr.$ If the river flows at the speed of $4\, km/hr,$ which of the two friends will return to place $A$ first?